The present invention relates to magnetic cards usable with toy magnetically actuated, fluid display devices.
U.S. Pat. Nos. 4,143,472 and 5,151,032 describe aspects of a magnetically actuated, fluid display device typically distributed as a toy. The device includes a pair of planar parallel substrates spaced apart from one another by an open matrix spacer defining a multiplicity of adjoining cells. The cells are filled with a liquid dispersion comprising magnetic particles in a liquid dispersion medium. The dispersion medium has a viscosity sufficient to normally suspend the magnetic particles in a fixed position. The particles can be moved by a sufficiently strong, externally applied magnetic field. The toy is typically provided with a quill having a permanent magnet tip that draws the magnetic particles to one of the panels against which the quill tip is applied. By providing contrasting colors to the magnetic particles and the dispersion medium, the particles drawn to the surface of the substrate change the color of the cell, thereby creating a visible image on the face or "screen" of the display device.
A number of accessories have been proposed thus far for use with such magnetic fluid display devices. Magnetic "stamps" in various shapes (e.g. large solid circle, large hollow tube, other geometric shapes, etc.), have been provided with handles to easily reproduce individual images of such shapes on the display. Also, conventional stencils having open slots, which permit the magnetic tip of the quill to contact the surface of the display, can be used to assist in making shapes.
It would be desirable to provide other accessories for use with the magnetic board, particularly educational accessories, to add to the entertainment, enjoyment and learning of users who already own such boards and to make such boards more versatile and therefore more desirable to potential purchasers.